diff --git a/libmproxy/proxy.py b/libmproxy/proxy.py
index 280bab936..0941155f9 100644
--- a/libmproxy/proxy.py
+++ b/libmproxy/proxy.py
@@ -228,9 +228,9 @@ class Request(controller.Msg):
 
 class Response(controller.Msg):
     FMT = '%s\r\n%s\r\n%s'
-    def __init__(self, request, code, proto, msg, headers, content, timestamp=None):
+    def __init__(self, request, code, msg, headers, content, timestamp=None):
         self.request = request
-        self.code, self.proto, self.msg = code, proto, msg
+        self.code, self.msg = code, msg
         self.headers, self.content = headers, content
         self.timestamp = timestamp or time.time()
         self.cached = False
@@ -239,7 +239,6 @@ class Response(controller.Msg):
     def get_state(self):
         return dict(
             code = self.code,
-            proto = self.proto,
             msg = self.msg,
             headers = self.headers.get_state(),
             timestamp = self.timestamp,
@@ -251,7 +250,6 @@ class Response(controller.Msg):
         return klass(
             request,
             state["code"],
-            state["proto"],
             state["msg"],
             utils.Headers.from_state(state["headers"]),
             state["content"],
@@ -438,7 +436,7 @@ class ServerConnection:
             content = None
         else:
             content = read_http_body(self.rfile, self, headers, True)
-        return Response(self.request, code, proto, msg, headers, content)
+        return Response(self.request, code, msg, headers, content)
 
     def terminate(self):
         try:
diff --git a/test/test_filt.py b/test/test_filt.py
index 43addd3e0..6f8579d3f 100644
--- a/test/test_filt.py
+++ b/test/test_filt.py
@@ -93,7 +93,6 @@ class uMatching(libpry.AutoTree):
         return proxy.Response(
                     q,
                     200,
-                    "HTTP/1.1",
                     "message",
                     headers,
                     "content_response"
diff --git a/test/test_proxy.py b/test/test_proxy.py
index 396897460..bb1a21229 100644
--- a/test/test_proxy.py
+++ b/test/test_proxy.py
@@ -237,7 +237,7 @@ class uResponse(libpry.AutoTree):
         h["test"] = ["test"]
         c = proxy.ClientConnection(("addr", 2222))
         req = proxy.Request(c, "host", 22, "https", "GET", "/", h, "content")
-        resp = proxy.Response(req, 200, "HTTP", "msg", h.copy(), "content")
+        resp = proxy.Response(req, 200, "msg", h.copy(), "content")
         assert resp.short()
         assert resp.assemble()
 
diff --git a/test/utils.py b/test/utils.py
index 94463b6a0..b63c48dc2 100644
--- a/test/utils.py
+++ b/test/utils.py
@@ -13,7 +13,7 @@ def tresp(req=None):
         req = treq()
     headers = utils.Headers()
     headers["header_response"] = ["svalue"]
-    return proxy.Response(req, 200, "HTTP/1.1", "message", headers, "content_response")
+    return proxy.Response(req, 200, "message", headers, "content_response")
 
 
 def tflow():